Free Pythagorean Theorem Calculator – Find Missing Sides

Geometry Tool

Pythagorean Theorem Calculator

Use the Pythagorean theorem to solve for a missing side of a right triangle. Enter two known sides and calculate side a, side b, or hypotenuse c.

Enter two known sides

Choose which side you want to solve for, then enter the two known measurements. The calculator uses a² + b² = c².

b a c 90°
Formula used:
a² + b² = c²
c = √(a² + b²)
a = √(c² − b²)
b = √(c² − a²)
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Missing Side 0
Triangle Area 0
Side a
0
Side b
0
Side c
0
Perimeter 0
Formula applied
Right triangle check Valid right triangle
This calculator assumes a right triangle where a and b are the legs and c is the hypotenuse. The hypotenuse must always be the longest side.